First, clear all the browser's cached data. To do so, open safari and navigate to the upper left hand side of the screen. Click Safari then Preferences. Now click the Advanced tab. In this list, check Show Develop menu in menu bar. Now go back to the main Safari window and select the Develop option at the top of the screen and click Empty Caches.

Next, delete all extensions what were downloaded. To do so, open safari and navigate to the upper left hand side of the screen. Click Safari then Preferences. Now click the Extensions tab. Select all extensions, and click the Uninstall button.

Next, delete all plugins that were installed (this can be done by simply disabling them). To do so, open safari and navigate to the upper left hand side of the screen. Click Safari then Preferences. Now click the Security tab. Deselect the Allow Plug-ins option.